1. Field of the Invention
The present invention relates to a ferroelectric memory including memory cells each comprised of a single selection transistor and a single ferroelectric capacitor and storing data by the direction of polarization of the ferroelectric capacitors.
2. Description of the Related Art
There is known a ferroelectric memory comprising memory cells including ferroelectric capacitors using as a capacitor insulating film a ferroelectric material of an oxide of a perovskite structure such as BaTiO.sub.3, SrTiO.sub.3, or PbTiO.sub.3 and storing data by the direction of polarization Of the ferroelectric capacitors.
When forming a memory cell of such a ferroelectric memory by a single transistor and single capacitor, however, the difference in potential between the read bit line connected to the memory cell and the reference bit line connected to the reference cell is small, so it is not easy to ensure a sufficient margin needed for the read operation. On the other hand, when forming a memory cell by two transistors and two capacitors, it becomes easy to secure a sufficient margin required for the read operation, but the memory cell becomes larger in area--which is disadvantageous when trying to construct a large capacity memory.